Technical Field
The present invention relates to the field of motor control, and particularly to a position-sensorless control method and apparatus for a brushless motor.
Related Art
A brushless motor replaces mechanical commutation with electronic commutation, overcomes a series of problems produced by the traditional DC motor due to brush friction, and has advantages such as good speed control performance, small volume and high efficiency, and thus is widely applied to various fields of production of national economy and people's daily life.
The brushless motor generally uses one or more position sensors to detect a position of a motor rotor, and accordingly applies driving voltages to respective phase coils of the motor, to drive the motor to rotate. Problems such as installation space, installation error and high temperature failure brought about by the position sensors restrict applications of position sensor schemes in fields such as range hoods, and increase the system cost. Through parameter detection such as phase currents and voltages and position-sensorless algorithms such as sliding mode and state observer, position-sensorless motor control can be achieved, but such algorithms have high requirements for software and hardware of a control apparatus, are more sensitive to motor parameters, and generally have a higher cost.